1. Field of the Invention
This invention relates to well tools and more particularly to locking devices and latches therefor.
2. Description of the Prior Art
Latches for locking flow control devices and other well tools in landing receptacles of well flow conductors are well known and usually include expansible and retractable lock means which engage an internal annular or semi-annular lock shoulder formed near the upper end of the landing receptacle bore. Good examples of such latch devices are illustrated and described in U.S. Pat. Nos. 2,690,056, 3,074,485, 3,741,601, and 3,837,398.
U.S. Pat. No. 2,698,056 to S. J. E. Marshall et al. shows a device having a housing provided with windows in the wall thereof, a locking lug in each of the windows movable between retracted and expanded positions, a tubular core secured in the mandrel about the core and slidable between an upper position wherein it allows the lugs to retract and a lower position wherein it locks the lugs in expanded locked position after it has expanded them.
U.S. Pat. No. 3,074,485 shows various latch devices having a lock sleeve mounted for axial movement about a core and adapted to lock and unlock a lock ring which moves between concentric and eccentric positions to lock or unlock the latch in a landing receptacle.
U.S. Pat. No. 3,741,601 shows a latch having a body with a core projecting upwardly. A lock sleeve is mounted about the core for limited axial movement relative thereto and is secured in its lower locking position on the core by a transverse shear pin. A collet having dependent fingers with internal and external bosses formed on the lower ends thereof is disposed about the lock sleeve for limited axial movement thereon. When the collet is in its lower position, the fingers cannot retract to release position. When the lock sleeve is lifted, the collet fingers can retract allowing the latch to be withdrawn from its receptacle.
A similar device is shown in the catalog of GAS LIFT EQUIPMENT AND SERVICES, OEC 5122, published November 1976 by Otis Engineering Corporation, P.O. Box 34380, Dallas, Tex. 75234. It appears on page 35 of that catalog and is designated the "Type T2" latch. The Type T2 latch appears to be an improvement over the latch of U.S. Pat. No. 3,741,601, the improvement appearing to reside in an outer sleeve surrounding the collet and having windows in the wall thereof through which the collet fingers are movable radially outwardly to expanded locking position. This sleeve appears to be integral with the body. In this device the collet fingers can move longitudinally up and down in the windows as well as radially in and out between locked and unlocked positions.
None of the prior art devices discussed above having locking lugs mounted in windows of a tool body for both radial and longitudinal movement between locked and unlocked positions with the lugs being spring-biased downwardly therein to positively move the lugs to locking position.